After being formed into predetermined shapes, sheet metal parts and composite material parts of aircraft are subjected to a trimming to have exact dimensions specified in drawings. As a trimming method, there are known a method in which a special jig is used to provide a marking line on a part and a trimming is performed along the marking line, a method in which a tool is moved along a special guide jig fixed to a part so as to perform a trimming, and a method in which an NC (numerical control) processing device is used to perform a trimming. It is difficult to automate the method in which a trimming is performed along the marking line. In the method in which a tool is moved along a special guide jig fixed to a part so as to perform a trimming, a special jig is required for each part and an exact alignment is required in attaching the jig to the part. Also, in the method in which an NC processing device is used to perform a trimming, an exact alignment of a part is required.
Japanese Patent Publication (JP-P2005-342865A) discloses a processing device for performing a trimming by tracing a shape of apart. The processing device includes a tool for trimming a to-be-processed material and a guide jig. The guide jig includes a contacting portion and a holding portion attached to the contacting portion. The holding portion holds the tool. The contacting portion includes a contacting surface which contacts a reference surface extending in a longitudinal direction of the to-be-processed material and moves in the longitudinal direction with the contacting surface contacting the reference surface. The tool moves along a locus corresponding to a shape of the reference surface to form a trimmed shape on the to-be-processed material. According to the trimming by tracing a shape of a part, an exact alignment is not necessary.
However, since the shape of the reference surface is reflected in the trimmed shape as it is, when recesses and protrusions are provided to the reference surface, recesses and protrusions corresponding to those recesses and protrusions are provided to the trimmed shape. When the recesses and protrusions of the reference surface are necessary but the recesses and protrusions of the trimmed shape are unnecessary, such inflexibility of the trimming by tracing the shape of part will provide a problem.
Japanese Patent Publication (JP-A-Heisei 11-123634) discloses another processing device for performing a trimming by tracing a shape of apart. The processing device includes a processing tool unit, a numerical control unit, measuring means, and tool path deriving means. The measuring means are driven and controlled by the numerical control unit to measure a dimension distribution in a to-be-processed material. The tool path deriving means derives a tool path based on the measurement result by the measuring means. The numerical control unit moves the processing tool unit along the tool path.